<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        function jumpTo(){
            var value = document.getElementsByTagName("select")[0].value;
            switch (value){
                case "ct":
                    location.href = "seasons/c.html";
                    break;
                case "xt":
                    location.href = "seasons/x.html";
                    break;
                case "qt":
                    location.href = "seasons/q.html";
                    break;
                case "dt":
                    location.href = "seasons/d.html";
            }
        }
    </script>
</head>
<body>
    <select onchange="jumpTo()">
        <option value="-1">--请选择--</option>
        <option value="ct">春天</option>
        <option value="xt">夏天</option>
        <option value="qt">秋天</option>
        <option value="dt">冬天</option>
    </select>
</body>
</html>